U.S. patent application number 13/908377 was filed with the patent office on 2013-12-05 for sensor unit and motion measurement system using the same.
The applicant listed for this patent is Seiko Epson Corporaion. Invention is credited to Kazumasa Mizuta.
Application Number | 20130319113 13/908377 |
Document ID | / |
Family ID | 49668634 |
Filed Date | 2013-12-05 |
United States Patent
Application |
20130319113 |
Kind Code |
A1 |
Mizuta; Kazumasa |
December 5, 2013 |
SENSOR UNIT AND MOTION MEASUREMENT SYSTEM USING THE SAME
Abstract
The first buffer portion provides a first base portion and a
first outer wall provided on a peripheral edge of the first base
portion. The second buffer portion provides a second base portion
which provides a mounting surface outside to a measurement target,
and a second outer wall provided on a peripheral edge of the second
base portion. The buffer body provides the first base portion and a
top surface of the second outer wall abutting against each other. A
housing portion for the sensor portion is provided inside. A
holding portion which holds the sensor portion is provided at least
at a part of the top surface of at least one of the first buffer
portion and the second buffer portion. The sensor portion is held
by the holding portion.
Inventors: |
Mizuta; Kazumasa; (Fujisawa,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Seiko Epson Corporaion |
Tokyo |
|
JP |
|
|
Family ID: |
49668634 |
Appl. No.: |
13/908377 |
Filed: |
June 3, 2013 |
Current U.S.
Class: |
73/493 |
Current CPC
Class: |
G01P 1/023 20130101;
G01P 1/003 20130101 |
Class at
Publication: |
73/493 |
International
Class: |
G01P 1/02 20060101
G01P001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 5, 2012 |
JP |
2012-127814 |
Claims
1. A sensor unit comprising: a buffer body comprising a first
buffer portion and a second buffer portion that abuts against the
first buffer portion and is softer than the first buffer portion;
and a sensor portion arranged inside the buffer body; wherein the
first buffer portion provides a first base portion and a first
outer wall provided on a peripheral edge of the first base portion,
the second buffer portion provides a second base portion which
provides a mounting surface outside to a measurement target, and a
second outer wall provided on a peripheral edge of the second base
portion, the buffer body provides the first base portion and the
second base portion facing each other and also provides a top
surface of the first outer wall and a top surface of the second
outer wall abutting against each other, and a housing portion for
the sensor portion is provided inside, and a holding portion which
holds the sensor portion is provided at least at a part of the top
surface of at least one of the first buffer portion and the second
buffer portion, and the sensor portion is held by the holding
portion.
2. The sensor unit according to claim 1, wherein the housing
portion is filled with a filler.
3. The sensor unit according to claim 1, wherein the sensor portion
provides a sensor mounted on a substrate, and a peripheral edge
portion of the substrate is held by the holding portion.
4. The sensor unit according to claim 3, wherein there is a gap
between the substrate and at least one of the top surface of the
first outer wall and the top surface of the second outer wall.
5. The sensor unit according to claim 1, wherein the first buffer
portion and the second buffer portion are fitted with each
other.
6. The sensor unit according to claim 1, wherein the second buffer
portion provides a smaller specific gravity than the first buffer
portion.
7. A motion measurement system including the sensor unit according
to claim 1.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present invention relates to a sensor unit and a motion
measurement system or the like using the sensor unit.
[0003] 2. Related Art
[0004] According to the related art, when a measurement device such
as a motion sensor which detects acceleration, angular velocity and
the like is mounted on a measurement target such as sporting
equipment, a shock and vibration absorber is arranged between the
measurement device and the measurement target. As the shock and
vibration absorber damps a shock and vibration from the measurement
target, the measurement device carries out accurate measurement
without being affected by the shock and vibration.
[0005] According to JP-A-1-302169, a buffer is mounted on an outer
surface of an exterior package of an acceleration sensor, thus
preventing the sensor from being damaged by a fall when the sensor
is carried around. The literature discloses the acceleration sensor
can be mounted on a vehicle via the buffer.
[0006] According to JP-A-3-170065, on a first member with high
mechanical strength which supports a substrate of an acceleration
sensor, a buffer is provided parallel to a connector unit. As the
connector is connected to a main body unit, the buffer is laid
between the acceleration sensor and the main body unit.
[0007] According to JP-UM-A-7-008775, an elastic cover body with
high shock absorptivity covers a housing of an acceleration sensor.
According to JP-A-9-145738, a buffer is provided between an
acceleration sensor and a substrate.
[0008] However, JP-A-1-302169 to JP-A-9-145738 do not disclose a
structure to install a sensor portion such as an acceleration
sensor onto sporting equipment.
[0009] FIG. 1 shows a comparative example in which when a sensor
portion 2 is mounted on sporting equipment, for example, on a
mounting surface 1b provided at a grip end 1a of a tennis racket 1,
a shock and vibration absorber 3 is provided as in-between, as in
JP-A-1-302169 to JP-A-9-145738. In the case where a motion of the
tennis racket 1 is measured by the sensor portion 2, the shock and
vibration absorber 3 can be provided as in-between as in the
comparative example of FIG. 1 in order to prevent direct
transmission of a shock and vibration generated when the tennis
racket 1 strikes a ball to the sensor portion 2.
[0010] Here, in order for the shock and vibration absorber 3 to
absorb a strong shock and vibration at the time of striking, it is
necessary to increase the volume of the shock and vibration
absorber 3 or switch to a material that can easily absorb a shock
and vibration.
[0011] However, if the volume of the shock and vibration absorber 3
is increased, for example, as shown in FIG. 2, the shock and
vibration absorber 3 becomes heavier, making the whole racket 1
heavier and also changing weight balance of the tennis racket 1.
The shock and vibration absorber 3 protruding as shown in FIG. 2
becomes an obstruction when a user holds the grip of the tennis
racket 1.
[0012] Meanwhile, if the material of the shock and vibration
absorber 3 is softened so that the material can easily absorb a
shock and vibration, as shown in FIG. 3, the sensor portion 2
itself swings, for example, in the direction of arrows shown in
FIG. 3 and cannot measure the motion of the tennis racket 1
accurately.
SUMMARY
[0013] An advantage of some aspects of the invention is to solve at
least apart of the problems described above, and some aspects of
the invention can be implemented as the following forms or
application examples.
Application Example 1
[0014] This application example of the invention is directed to a
sensor unit including: a buffer body having a first buffer portion
and a second buffer portion that abuts against the first buffer
portion and is softer than the first buffer portion; and a sensor
portion arranged inside the buffer body. The first buffer portion
provides a first base portion and a first outer wall provided on a
peripheral edge of the first base portion. The second buffer
portion provides a second base portion which provides a mounting
surface outside to a measurement target, and a second outer wall
provided on a peripheral edge of the second base portion. The
buffer body provides the first base portion and the second base
portion facing each other and also provides a top surface of the
first outer wall and a top surface of the second outer wall
abutting against each other. A housing portion for the sensor
portion is provided inside. A holding portion which holds the
sensor portion is provided at least at a part of the top surface of
at least one of the first buffer portion and the second buffer
portion. The sensor portion is held by the holding portion.
[0015] According to such a sensor unit, the first buffer portion
and the second buffer portion that is softer than the first buffer
portion are provided in the buffer body. The sensor portion is held
by the holding portion provided at least a part of the top surface
of at least one of the first buffer portion and the second buffer
portion. In the sensor unit, since the first buffer portion is
provided in such a way as to hold the second buffer portion down,
the second buffer portion can be deformed easily, thus restraining
transmission of a shock and vibration to the sensor portion. The
first buffer portion absorbs an excess shock and vibration that
cannot be absorbed by the second buffer portion.
Application Example 2
[0016] In the sensor unit according to the above application
example, it is preferable that the housing portion is filled with a
filler.
[0017] According to such a sensor unit, since the void is filled
with the filler, the filler can hold the sensor portion. The filler
absorbs deformation of the second buffer portion and can reduce
transmission of the deformation to the sensor portion. Moreover,
the filler can hold the sensor portion in a hollow state without
making the sensor portion directly contact the second buffer
portion. Therefore, transmission of a shock and vibration can be
minimized.
Application Example 3
[0018] In the sensor unit according to the above application
example, it is preferable that the sensor portion provides a sensor
mounted on a substrate and that a peripheral edge portion of the
substrate is held by the holding portion.
[0019] According to such a sensor unit, the substrate provided in
the sensor portion is held by the holding portion with a gap to
avoid abutting against the first buffer portion. Thus, transmission
of a shock and vibration from the first buffer portion to the
sensor portion held by the holding portion of the second buffer
portion can be restrained. Also, since a shock and vibration
applied to the second buffer portion is transmitted to the first
outer wall abutting against the second outer wall, by providing a
gap between the first buffer portion and the substrate,
transmission of a shock and vibration transmitted to the first
buffer portion to the sensor portion via the substrate held by the
holding portion can be restrained.
Application Example 4
[0020] In the sensor unit according to the above application
example, it is preferable that there is a gap between the substrate
and the top surface.
[0021] According to such a sensor unit, a gap is provided between
the substrate and the top surface, and the sensor portion is
provided in the housing portion. In the sensor unit, a shock and
vibration is absorbed mainly by the deformation of the second
buffer portion and transmission of the shock and vibration to the
sensor portion provided in the housing portion can be restrained.
Also, in the case where a gap is provided between the substrate and
the top surface, and the housing portion is a void, the sensor
portion cannot abut against the buffer body except on the holding
portion. Therefore, direct transmission of the shock and vibration
to the sensor portion can be restrained.
Application Example 5
[0022] In the sensor unit according to the above application
example, it is preferable that the first buffer portion and the
second buffer portion are fitted with each other.
[0023] According to such a sensor unit, the top surface of the
first buffer portion and the second buffer portion are fitted with
each other. Therefore, a shock and vibration from a measurement
target is absorbed by the deformation of the second buffer portion.
Moreover, when an excess shock and vibration that cannot be
absorbed by the second buffer portion is transmitted to the first
buffer portion, a shift of the first buffer portion and the second
buffer portion from each other can be restrained.
Application Example 6
[0024] In the sensor unit according to the above application
example, it is preferable that the second buffer portion provides a
smaller specific gravity than the first buffer portion.
[0025] According to such a sensor unit, since the second buffer
portion provides a smaller specific gravity than the first buffer
portion, the first buffer portion can have a greater weight than
the second buffer portion and deformation of the second buffer
portion by the weight of the first buffer portion can be
restrained.
Application Example 7
[0026] This application example of the invention is directed to a
motion measurement system including the above sensor unit.
[0027] According to such a motion measurement system, since the
system includes the above sensor unit, the buffer body can absorb
an excessive shock and vibration that is generated, for example, by
a strike with a measuring target. Thus, an unwanted shock and
vibration for measurement of a motion of the measuring target can
be damped.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The invention will be described with reference to the
accompanying drawings, wherein like numbers reference like
elements.
[0029] FIG. 1 shows a comparative example in which a sensor portion
is fixed via a shock and vibration absorber to a grip end of a
tennis racket.
[0030] FIG. 2 shows a form in which the volume of the shock and
vibration absorber is increased in the comparative example shown in
FIG. 1.
[0031] FIG. 3 shows a form in which the material of the shock and
vibration absorber is softened in the comparative example shown in
FIG. 1.
[0032] FIG. 4 schematically shows a cross section of a sensor unit
according to a first embodiment.
[0033] FIG. 5 schematically shows a transmission effect of a shock
and vibration in the first embodiment.
[0034] FIG. 6 shows a transmission effect of a shock and vibration
in a rear-end collision state in the comparative example shown in
FIG. 1.
[0035] FIGS. 7A to 7C show measurement data of acceleration of a
shock and vibration applied to a sensor unit according to a
related-art example.
[0036] FIGS. 8A to 8C show measurement data of acceleration of a
shock and vibration applied to the sensor unit according to the
comparative example shown in FIG. 1.
[0037] FIGS. 9A to 9C shows measurement data of acceleration of a
shock and vibration applied to the sensor unit according to the
first embodiment.
[0038] FIG. 10 is a sectional view of a sensor unit according to a
second embodiment.
[0039] FIG. 11 is a sectional view of a sensor unit according to a
third embodiment.
[0040] FIG. 12 is a block diagram showing a motion measurement
system according to a fourth embodiment.
[0041] FIG. 13 is a block diagram showing details of a sensor
portion provided in a sensor unit according to the fourth
embodiment.
[0042] FIG. 14 is a sectional view of a sensor unit according to a
modification.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0043] Hereinafter, embodiments of the invention will be described
with reference to the drawings. In the drawings described below,
each component is shown in a large enough size to be recognized in
the drawings and therefore the dimension and proportion of each
component may be different from the actual component according to
need. Also, an XYZ orthogonal coordinate system is set and the
positional relation of each portion is described with reference to
this XYZ orthogonal coordinate system. A predetermined direction
within a vertical plane is defined as an X-axis direction. A
direction orthogonal to the X-axis direction within the vertical
plane is defined as a Y-axis direction. A direction orthogonal to
each of the X-axis direction and the Y-axis direction is defined as
a Z-axis direction. Referring to the gravitational direction, the
gravitational direction is defined as a downward direction and the
opposite direction is defined as an upward direction.
First Embodiment
[0044] FIG. 4 is a sectional view schematically showing a cross
section of a sensor unit according to a first embodiment of the
invention. A sensor unit 10a according to the first embodiment
shown in FIG. 4 provides a sensor portion 20 and a buffer body
30.
[0045] The sensor portion 20 provides a three-axis acceleration
sensor and a three-axis angular velocity sensor, and a drive
circuit and a signal processing circuit for the sensors, for
example, installed on face and back sides of a substrate 22a. The
maximum acceleration that can be measured by the sensor portion 20
is, for example, 50 G.
[0046] The buffer body 30 provides a first buffer portion 30a and a
second buffer portion 30b. The first buffer portion 30a provides a
first base portion 34a and a first outer wall 32a extending from
the first base portion 34a. The second buffer portion 30b provides
a second base portion 34b, a second outer wall 32b extending from
the second base portion 34b, and a holding portion 36 at one end
opposite to the second base portion 34b, of the second outer wall
32b. In the sensor unit 10a of this embodiment, plural first outer
walls 32a and second outer walls 32b are extending from the first
base portion 34a and the second base portion 34b. However, the
number of these walls is not limited to this example and a set of a
first outer wall 32a and a second outer wall 32b may be provided.
In this embodiment, a form in which two first outer walls 32a and
two second outer walls 32b are extending is described.
[0047] In the buffer body 30, the first base portion 34a and the
second base portion 34b fact each other and the first outer walls
32a and the second outer walls 32b abut against each other. The
second base portion 34b is bonded and fixed to the mounting surface
1b of the tennis racket 1 (see FIG. 1), for example, with a
double-side adhesive tape or the like, using a surface opposite to
the first base portion 34a as a mounting surface 34c. Also, the
buffer body 30 provides a housing portion 50 that is surrounded by
the first base portion 34a, the second base portion 34b, the first
outer walls 32a, and the second outer walls 32b.
[0048] In the buffer body 30, a shock and vibration transmitted
from the mounting surface 34c is absorbed by the second buffer
portion 30b. An excess shock and vibration that cannot be absorbed
there is transmitted from the second outer walls 32b to the first
outer walls 32a of the first buffer portion 30a and is absorbed by
the first buffer portion 30a.
[0049] The sensor portion 20 is provided in the housing portion 50.
A peripheral edge portion 22b that is an edge portion of the
substrate 22a is held by the holding portions 36 provided on top
surfaces 37b of the second outer walls 32b of the second buffer
portion 30b. The substrate 22a is held by the holding portions 36
with a gap to avoid abutment against top surfaces 37a provided on
the first outer walls 32a of the first buffer portion 30a.
Therefore, when a shock and vibration is transmitted from the
second outer walls 32b to the first outer walls 32a, transmission
of the shock and vibration to the sensor portion 20 via the
substrate 22a held there can be restrained.
[0050] While the holding portions 36 in this embodiment are
provided on the top surfaces 37b, the holding portions 36 may also
be provided on the top surfaces 37a. In such a case, the substrate
22a held by the holding portions 36 is provided in such a way as to
avoid abutting against the top surfaces 37b.
[0051] As the member used for the second buffer portion 30b, a
softer material than the member used for the first buffer portion
30a is used. In other words, as the member used for the first
buffer portion 30a, a harder material than the member used for the
second buffer portion 30b is used. Also, the second buffer portion
30b uses a member with smaller specific gravity than the first
buffer portion 30a. In other words, the first buffer portion 30a
uses a member with a greater specific gravity than the second
buffer portion 30b. In the buffer body 30, for example, if rubber
is used for the first buffer portion 30a, urethane foam can be used
for the second buffer portion 30b. The member used for the first
buffer portion 30a may be silicone resin and the like as well as
rubber. The member used for the second buffer portion 30b may be
polyurethane and the like as well as urethane foam.
[0052] The buffer body 30 in the first embodiment of the invention
provides a shock and vibration absorbing structure that is formed
as a two-stage structure. The first buffer portion 30a using the
harder material is superimposed on the second buffer portion 30b
using the softer material.
[0053] In the buffer body 30, since the first buffer portion 30a
made of the harder material and with a greater specific gravity is
superimposed on the second buffer portion 30b made of the softer
material and with a smaller specific gravity, the second buffer
portion 30b can be formed easily and can restrain a shock and
vibration. The first buffer portion 30a can absorb an excess shock
and vibration that cannot be absorbed by the second buffer portion
30b.
[0054] Thus, a shock and vibration that is generated when the
tennis racket 1 shown in FIG. 1 hits a ball or the like is absorbed
by the first buffer portion 30a and the second buffer portion 30b
of the sensor unit 10a and cannot be easily transmitted to the
sensor portion 20, as shown in FIG. 5.
[0055] On the other hand, in the comparative example shown in FIGS.
1 to 3, a shock and vibration that is generated when the tennis
racket 1 strikes an object or the like is absorbed by the shock and
vibration absorber 3 and thus damped, as shown in FIG. 6. However,
since the sensor portion 2 exists in the escape path of the shock
and vibration that cannot be absorbed by the shock and vibration
absorber 3, an excessive shock and vibration is directly
transmitted to the sensor portion 2 in a so-called rear-end
collision state.
[0056] In FIG. 4, the housing portion 50 as an in-between can be
further provided between the second buffer portion 30b and the
sensor portion 20. Thus, deformation of the second buffer portion
30b can be absorbed by the housing portion 50 and therefore
transmission of a shock and vibration to the sensor portion 20 can
be reduced further.
[0057] In the buffer body 30, the housing portion 50 can allow
(absorb) deformation generated in the second outer walls 32b and
the second base portion 34b by a shock and vibration. This housing
portion 50 can be a void (air gap). By forming the housing portion
50 as a void, deformation of the second buffer portion 30b is
absorbed by the housing portion 50 and transmission of the
deformation to the sensor portion 20 can be reduced.
[0058] FIGS. 7A to 9C show graphs illustrating the results of shock
and vibration tests.
[0059] FIGS. 7A to 7C show graphs illustrating the results of
measurement in which the sensor portion 2 is mounted via amounting
jig onto the mounting surface 1b of the tennis racket 1 shown in
FIG. 1 (without the shock and vibration absorber 3).
[0060] FIGS. 8A to 8C show graphs illustrating the results of
measurement in which the sensor portion 2 is mounted via the shock
and vibration absorber 3 by the method of the comparative example
shown in FIG. 1.
[0061] FIGS. 9A to 9C show graphs illustrating the results of
measurement in which the sensor unit 10a of this embodiment shown
in FIG. 4 is mounted on the mounting surface 1b of the tennis
racket 1 shown in FIG. 1.
[0062] FIGS. 7A to 9C show data as a result of measuring
acceleration on three axes (X, Y and Z axes) when the tennis racket
1 is dropped in the Z-axis direction from the same height.
[0063] FIG. 7A, FIG. 8A and FIG. 9A each show acceleration in the
Z-axis direction. FIG. 7B, FIG. 8B and FIG. 9B each show
acceleration in the Y-axis direction. FIG. 7C, FIG. 8C and FIG. 9C
each show acceleration in the X-axis direction. A comparison
between the graphs shown in FIGS. 7A to 7C and FIGS. 8A to 8C shows
that the time when a strong shock (acceleration) in the Z-axis
direction is received is shorter in the graph of FIG. 8A. This can
be recognized as the effect of inserting the shock and vibration
absorber 3 of FIG. 1. Meanwhile, the graphs of FIGS. 8B and 8C show
greater changes in acceleration in the X and Y-axis directions than
in the graphs shown in FIGS. 7B and 7C. It can be considered that
this is because the swing of the sensor portion 2 itself becomes
larger as the shock and vibration absorber 3 of FIG. 1 is
inserted.
[0064] Meanwhile, in the graph shown in FIG. 9A illustrating data
as a result of measurement by the sensor unit 10a of this
embodiment, the time when a strong shock (acceleration) in the
Z-axis direction is received is much shorter than in the graph
shown in FIG. 8A, and the time when the influence of a shock and
vibration is received is shorter also in the X-axis direction and
the Y-axis direction, as shown in the graphs of FIGS. 9B and 9C.
Thus, high effects can be confirmed.
[0065] The sensor unit 10a of the embodiment provides the following
effects.
[0066] According to such a sensor unit 10a, the sensor portion 20
which measures acceleration and the like of a measurement target is
provided in the buffer body 30 with a structure in which the first
buffer portion 30a and the second buffer portion 30b which are
different in specific gravity and hardness are superimposed on each
other. Thus, in the sensor unit 10a, the second buffer portion 30b
is deformed to absorb a shock and vibration from a measurement
target and the deformation of the second buffer portion 30b is
restrained by the first buffer portion 30a. Therefore, transmission
of the shock and vibration to the sensor portion 20 can be
restrained.
Second Embodiment
[0067] A sensor unit 10b according to a second embodiment of the
invention is shown in FIG. 10. The sensor unit 10b shown in FIG. 10
is different from the sensor unit 10a shown in FIG. 4 in that a
part of the first outer wall 32a and a part of the second outer
wall 32b of the buffer body 30 extend respectively and the first
buffer portion 30a and the second buffer portion 30b are jointed
together in a box-joint form. Hereinafter, different features from
the sensor unit 10a according to the first embodiment are
described, whereas the same configurations are denoted by the same
reference numerals and the description thereof is partly
omitted.
[0068] The sensor unit 10b provides a sensor portion 20 and a
buffer body 30, similarly to the sensor unit 10a according to the
first embodiment. The buffer body 30 provides a first buffer
portion 30a and a second buffer portion 30b made of different
materials from each other. The buffer body 30 also provides a
housing portion 50 that is surrounded by the first buffer portion
30a and the second buffer portion 30b.
[0069] As shown in FIG. 10, in the buffer body 30 of the sensor
unit 10b, the first outer wall 32a of the first buffer portion 30a
and the second outer wall 32b of the second buffer portion 30b are
jointed together in a box-joint form. The first outer wall 32a
extends a portion substantially half its thickness so as to
protrude as a box joint portion 33a toward the second outer wall
32b. The second outer wall 32b extends a portion substantially half
its thickness and different from the extended portion of the box
joint portion 33a when joined with (fitted with) the first outer
walls 32a, so as to protrude as a box joint portion 33b toward the
first outer wall 32a.
[0070] In the buffer body 30, a holding portion 36 is provided
between the box joint portion 33b extending toward the second outer
wall 32b and the second outer wall 32b. The sensor portion 20 is
provided in the housing portion 50, as in the sensor unit 10a. A
peripheral edge portion 22b that is an edge portion of a substrate
22a is held by the holding portion 36 provided on the second buffer
portion 30b.
[0071] The sensor unit 10b of the embodiment provides the following
effect.
[0072] The sensor unit 10b provides a structure such that when the
sensor unit 10b receives a shock and vibration, the shock and
vibration is absorbed by the first buffer portion 30a and the
second buffer portion 30b and is not easily transmitted to the
sensor portion 20, as in the foregoing sensor unit 10a. Also, in
the buffer body 30, since the first outer wall 32a and the second
outer wall 32b are jointed together in a box-joint form, the area
where the first outer wall 32a and the second outer walls 32b abut
against each other is greater than in the sensor unit 10a. Thus, in
the sensor unit 10b, a shock and vibration transmitted from the
mounting surface 34c is absorbed by the second buffer portion 30b,
and when the shock and vibration is transmitted to the first buffer
portion 30a, the transmission to the first buffer portion 30a can
be made efficiently. Moreover, when the shock and vibration is
transmitted from the second buffer portion 30b to the first buffer
portion 30a, a "shift" of the first buffer portion 30a and the
second buffer portion 30b from each other can be restrained.
Third Embodiment
[0073] A sensor unit 10c according to a third embodiment is shown
in FIG. 11. The sensor unit 10c shown in FIG. 11 is different from
the sensor unit 10a shown in FIG. 4 in that the housing portion 50
having a void is filled with a filler 60. Different features from
the sensor unit 10a according to the first embodiment are
described, whereas the same configurations are denoted by the same
reference numerals and the description thereof is partly
omitted.
[0074] The filler 60 fills the gap between a first outer wall 32a,
a second outer wall 32b, a first base portion 34a and a second base
portion 34b, and a sensor portion 20. In other words, the filler 60
fills the void of the housing portion 50 in which the sensor
portion 20 is provided. As the filler 60, a member that solidifies
after filling the void is used. In this embodiment, for example, a
potting material such as trade name TSE3051 (TANAC Co., Ltd.) or
trade name 1230G (ThreeBond Co., Ltd.) can be preferably used as
the filler 60.
[0075] While the sensor portion 20 is held by the holding portion
36 provided on the top surface 37b of the second outer wall 32b in
the foregoing example as shown in FIG. 4, a substrate 22a of the
sensor unit 10c according to the third embodiment shown in FIG. 11
need not be held since the filler 60 fills the housing portion 50.
This is because the sensor portion 20 can be held by the filler 60
within the housing portion 50. Thus, the sensor portion 20 does not
directly contact the second buffer portion 30b (second outer wall
32b), transmission of deformation of the second buffer portion 30b
to the sensor portion 20 can be restrained. Therefore, the swing of
the sensor portion 20 due to a shock and vibration can be
reduced.
[0076] As the sensor unit 10c, a form in which the housing portion
50 of the sensor unit 10a shown in FIG. 4 is filled with the filler
60 is described. However, a form in which the housing portion 50 of
the sensor unit 10b shown in FIG. 10 is filled with the filler 60
may also be employed.
[0077] The sensor unit 10c of the embodiment provides the following
effects.
[0078] According to the sensor unit 10c, the sensor portion 20 can
be fixed to the first base portion 34a of the first buffer portion
30a via the filler 60 filling the housing portion 50. Thus, the
sensor portion 20 is fixed via the filler 60 onto the first base
portion 34a having the least deformation in the buffer body 30 and
therefore the swing of the sensor portion 20 can be reduced. Also,
since the sensor portion 20 does not directly abut against the
buffer body 30, transmission of a shock and vibration to the sensor
portion 20 from the buffer body 30 can be restrained.
Fourth Embodiment
[0079] FIG. 12 shows the configuration of a motion measurement
(analysis) system according to this embodiment. A motion
measurement system 100 of this embodiment includes one of the above
sensor units 10a, 10b, 10c (hereinafter referred to as a "sensor
unit 10" where the unit is called by a general term) and a host
terminal 150, and measures and analyzes a motion of a measurement
target (for example, the tennis racket 1). The sensor portion 20
provided in the sensor unit 10 and the host terminal 150 may be
connected wirelessly or wire-connected.
[0080] The sensor unit 10 is mounted on a measurement target of
motion measurement (analysis), for example, on the tennis racket 1
shown in FIG. 1, and carries out processing to detect a
predetermined physical quantity. In this embodiment, the sensor
portion 20 includes, for example, plural sensors 102x to 102z and
104x to 104z, a data processing unit 110, and a communication unit
120, also as shown in FIG. 13.
[0081] Here, the sensors are sensors which detect a predetermined
physical quantity and output a signal (data) corresponding to the
magnitude of the detected physical quantity (for example,
acceleration, angular velocity and the like). In this embodiment, a
six-axis motion sensor including three-axis acceleration sensors
102x to 102z which detect acceleration in the X-axis direction,
Y-axis direction and Z-axis direction (an example of an inertial
sensor) and three-axis gyro sensors 104x to 104z which detect
angular velocity in the X-axis direction, Y-axis direction and
Z-axis direction (an example of an angular velocity sensor and
inertial sensor) is provided.
[0082] The data processing unit 110 carries out processing to
synchronize output data from the respective sensors 102x to 102z
and 104x to 104z, combine the output data with time information and
the like to form a packet, and output the packet to the
communication unit 120. The data processing unit 110 may also carry
out processing of bias correction and temperature correction on the
sensors 102x to 102z and 104x to 104z. The functions of bias
correction and temperature correction may be incorporated in the
sensors themselves.
[0083] The communication unit 120 carries out processing to
transmit the packet data received from the data processing unit
110, to the host terminal 150.
[0084] The host terminal 150 shown in FIG. 12 includes a processing
unit (CPU) 200, a communication unit 210, an operation unit 220, a
ROM 230, a RAM 240, a non-volatile memory 250, and a display unit
260.
[0085] The communication unit 210 carries out processing to receive
the data transmitted from the sensor portion 20 and send the data
to the processing unit 200. The operation unit 220 carries out
processing to acquire operation data from a user and send the
operation data to the processing unit 200. The operation unit 220
is, for example, a touch panel display, button, key, microphone and
the like.
[0086] The ROM 230 stores programs for the processing unit 200 to
carry out various kinds of calculation and control processing, and
various programs and data to realize application functions. The RAM
240 is a storage unit which is used as a work area for the
processing unit 200 and which temporarily stores programs and data
read out from the ROM 230, data inputted from the operation unit
220, and results of arithmetic operations executed by the
processing unit 200 according to various programs. The non-volatile
memory 250 is a storage unit which records data that needs to be
saved for an extended period, of data generated in the processing
by the processing unit 200.
[0087] The display unit 260 is to display results of processing by
the processing unit 200, in the form of characters, graphs, or
other images. The display unit 260 is, for example, a CRT, LCD,
touch panel display, HDM (head-mounted display) and the like. Also,
the functions of the operation unit 220 and the display unit 260
maybe realized by a single touch panel display.
[0088] The processing unit 200 carries out various kinds of
calculation processing with respect to data received from the
sensor portion 20 via the communication unit 210 and various kinds
of control processing (display control to the display unit 260 and
the like) according to programs stored in the ROM 230.
[0089] In this embodiment, the processing unit 200 includes a data
acquisition unit 202, an arithmetic operation unit 204, a data
correction unit 206, and a motion measurement (analysis)
information generation unit 208. The data acquisition unit 202
carries out processing to acquire output data from the sensors 102x
to 102z and the sensors 104x to 104z . The acquired data is stored,
for example, in the RAM 240. The arithmetic operation unit 204
carries out arithmetic operation to calculate m-order time
integration of the output data from the sensor portion 20. Thus,
velocity data and position data are generated based on acceleration
data. Alternatively, an angle is generated based on angular
velocity data.
[0090] The data correction unit 206 corrects the result of the
arithmetic operation by the arithmetic operation unit 204, for
example, based on known data of a standstill state. The motion
measurement (analysis) information generation unit 208 carries out
processing to generate information for measuring (analyzing) a
motion of a measurement target (hereinafter referred to as "motion
analysis information"), based on the corrected data from the data
correction unit 206. The generated motion analysis information may
be displayed on the display unit 260 in the form of characters,
graphs, diagrams and the like, or may be outputted outside the host
terminal 150. The arithmetic operation unit 204, the data
correction unit 206, and the motion measurement (analysis)
information generation unit 208 are an example of a motion
measurement (analysis) unit.
[0091] The motion measurement system 100 of the embodiment provides
the following effects.
[0092] According to the motion measurement system 100, since the
system includes the sensor unit 10, an excessive shock and
vibration that is generated, for example, by hitting an object with
the measurement target, can be absorbed by the first buffer portion
30a and the second buffer portion 30b. Thus, measurement of an
unwanted shock and vibration for motion measurement of the
measurement target can be restrained and a predetermined physical
quality of the measurement object can be measured accurately.
[0093] The invention is not limited to the above embodiments and
various changes, improvements and the like can be added without
departing from the scope of the invention. A modification is
described hereinafter.
Modification 1
[0094] The sensor portion 20 in the sensor units 10a, 10b, 10c can
be an inertial measurement unit 20a. A sensor unit 10d shown in
FIG. 14 includes the inertial measurement unit 20a and a buffer
body 30, and the buffer body 30 includes a first buffer portion 30a
and a second buffer portion 30b, as in the sensor units 10a, 10b,
10c. The inertial measurement unit 20a is provided in a housing
portion 50, and a mounting portion 22c extending from the inertial
measurement unit 20a is held by a holding portion 36 provided on a
second outer wall 32b of the second buffer portion 30b. Thus, in
the sensor unit 10d, a shock and vibration can be absorbed by the
buffer body 30, for example, when the sensor unit 10d is mounted on
the tennis racket 1 (see FIGS. 1 to 3) and the like. Therefore,
transmission of the shock and vibration to the inertial measurement
unit 20a can be restrained.
[0095] The entire disclosure of Japanese Patent Application No.
2012-127814, filed Jun. 5, 2012 is expressly incorporated by
reference herein.
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